扰动激波冲击界面不稳定性:反射激波效应  

Instability of an interface subjected to a perturbed shock:reflected shock effects

作　　者：权通 廖深飞 邹立勇[2] 邱华[1] QUAN Tong;LIAO Shenfei;ZOU Liyong;QIU Hua(School of Power and Energy,Northwestern Polytechnical University,Xi’an 710072,China;National Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang Sichuan 621900,China)

机构地区：[1]西北工业大学动力与能源学院,西安710072 [2]中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室,四川绵阳621900

出　　处：《实验流体力学》2020年第5期12-19,共8页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金(11672277,11602247,51676164,91952205)。

摘　　要：通过平面激波绕刚体圆柱的方法形成扰动激波,采用无膜技术形成N 2/SF 6均匀界面,在竖式激波管中开展了扰动激波冲击界面Richtmyer-Meshkov(RM)不稳定性实验研究。针对3种不同的无量纲距离η(圆柱到界面距离与圆柱直径之比)情形,利用高速纹影技术及平面Mie散射技术,获得了反射激波二次冲击作用下的界面演化图像。前期工作(邹立勇等,2017)显示,入射激波冲击后,界面发展为包括中心气腔和两侧台阶的“Λ”形结构。研究结果表明:反射激波二次冲击后,“Λ”形界面首先经历相位反转,然后扰动逐渐发展增强。在η=2.0情形,界面演化为气泡,而当η=3.3和4.0时,在整体的气泡结构之外,界面中心发展为尖钉结构。获得了反射激波作用后的混合区宽度,并与理论模型结果进行了比较。在界面演化线性阶段,Meyer-Blewett(MB)线性模型结果和实验结果吻合较好。在界面演化非线性阶段,Dimonte-Ramaprabhu(DR)模型结果和实验结果吻合较好。特别地,当η=4.0时,理论与实验结果差别最小。The Richtmyer-Meshkov(RM)instability of a N 2/SF 6 interface subjected to a perturbed shock is investigated experimentally in a vertical shock tube.The perturbed shock is generated by a planar shock diffracting around a rigid cylinder and the initial uniform interface is formed by a membraneless method.Three different dimensionless distancesη(the ratio of spacing from the cylinder to the interface over the cylinder diameter)are considered.Dynamic images of the interface evolution after the impact of the reflected shock are obtained using both schlieren and planar Mie scattering techniques.Our previous study(Zou,et al.,2017)indicated that,after the impingement of the incident shock,the interface evolves into a“Λ”shape structure with two interface steps at both sides and a cavity at the center.The results in present paper show that,due to the impingement of the reflected shock,the“Λ”shape structure interface first experiences a fast phase reversal and then the perturbation increases gradually.Forη=2.0 case,the interface evolves into an overall bubble structure,while forη=3.3 andη=4.0 cases,a spike appears in the center of the interface besides the overall bubble.The mixing width is further measured from Mie scattering images and compared with the theoretical values.It is found that at the linear stage,the interface width can be predicted well by the linear model proposed by Meyer and Blewett,and at the nonlinear stage,the width can be reasonably estimated by the model proposed by Dimonte and Ramaprabhu.In particular,the distinction between the theoretical prediction and the experimental result is the lowest for the case ofη=4.0.

关 键 词：扰动激波 RM不稳定性 反射激波 混合区宽度 非线性模型 

分 类 号：O354.5[理学—流体力学]